Yarn handling and severing mechanism for circular knitting machines and methods



Feb. 12, 1963 H BUTLER 3,077,097

V. YARN HANDLING AND SEVERING MECHANISM FOR CIRCULAR KNITTING MACHINES AND METHODS Filed April 2, 1957 6 Sheets-Sheet 1 INVENTOR VAUGHN H. BUTLER ATTORNEY Feb. 12, 1963 v. H. BUTLER 3,077,097 YARN HAND ND SEVERI MECHANISM FOR CIRCULAR ms MACHI AND METHOD Filed April 2, 1957 6 eats-Sheet 2 INVENTOR VAUGHN H. BUT LER ATTORNEYS Feb. 12, 1963 v. H. BUTLER 3,077,097

YARN HANDLING AND SEVERING MECHANISM FOR CIRCULAR KNITTING MACHINES AND METHODS Filed April 2, 1957 6 Sheets-Sheet 3 FIG. 10. 72

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INVENTOR 54 VAUGHN H.BUTLE R WWW I ATTORNEYS Feb. 12, 1963 v. H. BUTLER 3,077,097

YARN HANDLING AND SEVERING MECHANISM FOR CIRCULAR KNITTING MACHINES AND METHODS 6 SheetsSheet 4 Filed April 2, 1957 FIGJ6'.

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INVENTOR VAU GH N H. BUTLER ATTORNEYS Feb. 12, 1963 v. H. BUTLER 3,077,097 YARN HANDLING AND SEVERING MECHANISM FOR CIRCULAR KNITTING MACHINES AND METHODS Filed April 2, 1957 6 Sheets-Sheet 5 FIG.1.9.

60 INVENTOR as" Q VAUGHN H. BUTLER \r.-/

BY Ill 84 W l if B /IIIHHlH||l\\\\\\ ATTORNEYS Feb. 12, 1963 v. H. BUTLER 3,077,097

YARN HANDLING AND SEVERING MECHANISM FOR CIRCULAR KNITTING MACHINES AND METHOD Filed April 2, 1957 6 eats-Sheet s FIGZZ.

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INVENTOR VAUGHN H. BUTLER ATTORNEYS s 017 097 YARN HANDLING Ann nvanmo MncnANrsM son CIRCULAR KNITTING MACHINES AND METHODS) This invention relates to circular knitting machines, and in particular to improved means and methods for handling and severing yarns on the dial caps thereof.

In the knitting of tubular articles such as seamless hosiery, frequent yarn changes are commonly effected in the course of the knitting cycle. In the case of hosiery, for example, the welt and leg may be knitted of different yarns, and heavier yarns are frequently employed in the heel and toe. At each yarn change, an inactive yarn is dropped into the needles for knitting and an active yarn is withdrawn from the knitting a few needles later. Two yarn ends extend from the resulting yarn lap, and these are commonly severed so as to be an inch or two in length. Since yarn ends of such length are easily noticeable and unsightly, they must be removed, and this is usually done individually and manually during inspection. The yarn ends are clipped down to A" or which is commercially satisfactory. The clipping operation is obviously time consuming and expensive, and exposes the stockings to possibility of damage.

A principal object of the present invention is the provision of novel means and methods for positioning yarns over the dial cap of the machine for clipping, and automatically severing the yarns close to the fabric during yarn changes, with such reliability and control as to eliminate subsequent inspection and clipping of free ends. Related objects are to provide a novel yarn shear disposed peripherally of the dial cap and very closely adjacent the needles, and means for positioning the yarn ends to extend substantially radially inwardly from the needles as they are severed. The invention contemplates the close clipping of the ends of both newly inserted and withdrawn yarns, preferably with a single shear stroke.

Another object of the invention is to provide novel means and methods for holding and tensioning yarns on the dial cap of the machine. Related objects are the provision of a suction device and pneumatically operated clamp, which cooperate to insure that all yarn ends are under positive control at all times. The yarn handling mechanism is distinct from the yarn severing mechanism and separately actuated, eliminating pulled ends and undesired disturbance of inactive yarns. The yarn handling means, furthermore, is automatically operative to tighten all yarns at every yarn lap, and is self cleaning. Further objects will be in part evident and in part pointed out hereinafter.

The invention and the novel features thereof may best be made clear from the following description and the accompanying drawings, in which:

FIGURE 1 is a side elevational view, partly broken away, illustrating a preferred embodiment of the invention in operative association with related parts of the knitting machine;

FIGURE 2 is a top FIGURE 1, with some clarity;

FIGURE 3 is a top plan view of the yarn handling mechanism of the invention, on enlarged scale;

FIGURE 4 is an end elevational view of the mechanism of FIGURE 3, looking toward the right hand side thereof;

plan view of the mechanism of parts removed for the sake of rates Patent Office 3,077,097 Patented Feb. 12, 1963 FIGURE 5 is a side elevational view of the mechanism FIGURE 3, looking toward the bottom of FIGURE 3; FIGURE 6 is a bottom plan view of the mechanism of FIGURE 3 FIGURE 7 is a sectional view taken on the line 7-7 of FIGURE 3;

FIGURE 8 of FIGURE 3;

FIGURE 9 is a sectional view taken on the line 9-9 of FIGURE 3;

FIGURE 10 is a side elevational view of the dial cap of FIGURE 1 and elements mounted thereon, looking toward the shear;

FIGURE 11 is a mounted shear;

FIGURE 12 is a plan view of the shear;

FIGURE 13 is a plan view of the cutaway dial cap plate which accommodates the shear; I

FIGURE 14 is a leading end elevational view of the shear,showing the rounded outside surface: of the movable shear blade;

FIGURE 15 is a sectional view taken on the line 15- 15 of FIGURE 11;

FIGURES 16 through 21 are plan views sequentially illustrating the operation of the invention throughout a yarn change;

FIGURE 22 is an elevational view of the pneumatic system of the invention;

FIGURE 23 is a side view of an exemplary ring cam actuating the pneumatic system, and

FIGURES 24 and 25 illustrate drum earns adapted to efiect the desired rate of operation of the shear.

Referring to the drawings in detail, FIGURES 1 and 2 illustrate a portion of a conventional seamless hosiery machine, such as a 400 needle Model KN Scott & Williams machine. As shown, the latch ring 30 encloses the knitting station indicated generally as 32, the latter being provided with a yarn guide plate 34 and a plurality of yarn fingers 36 which are individually retractable and function as interchangeable yarn feeds. The yarn fingers are pivotally mounted at 38, and actuated in conventional manner by thrust bars maintained in contact with the main pattern drum of the machine. Knitting yarns pass through eyes in the guide plate 34 and through the ends of the yarn fingers 3-6. Illustrated is an inactive yarn 40 controlled by finger 36', and an activ yarn 42 extending from finger 36" to the adjacent knitting needles 44 of the machine. As will be understood, other active and inactive yarns may be present, but are unnecessary for an understanding of the present invention. in the rotary cylinder of the machine (not shown), and extend thereabove adjacent the periphery of the dial and is a sectional view taken on the line 8-8 face 66 adapted to rest on the dial cap, to which the housing is attached as by means of screws 68. A horizontal bore 70 extends through the housing 64, and an air pressure conduit 72 communicates with one end of the bore 76- through the adapter"74, which terminates perspective view of the dial cap The needles 44 are independently mounted in a small diameter jet 76. As shown, the adapter 74 may be welded to the pressure conduit 72, and secured in the housing by screw 78. An exhaust conduit 80 extends from the other end of bore 70, its end being suitably retained as by screw 82. As will be understood, the pressure conduit 72, bore 70 and exhaust conduit 80 together constitute a continuous air path or conduit for air flow. A branch passage 84 extends downwardly from the intermediate section of bore 70, to the upwardly offset undersur-face 86 of the housing. Aswill b evident, with the bottom housing surface 66 resting on the dial cap, the undersurface 86 will be slightly spaced therefrom. The jet 76 of the adapter 74 is directed toward the end opening of exhaust conduit 80, these elements being adapted to function as an aspirator, to create suction in and induce air flow upwardly through the branch passage 84. A guide post 88 extends downwardly from the undersurface 86 adjacent branch passage 84, the post 88 being adapted to extend into an accommodating socket therefor in the dial cap.

A diagonal slot 92 extends across the top of the housing 64, and a pivotal clamp arm 94 is fitted to operate within the slot, being retained by its pivot pin 96. One end of the clamp arm 94 terminates in a yarn clamp 98 of conventional design, the yarn clamp being disposed substantially over the guid tongue 60, at a position leading the housing 64 with respect to the direction of cylinder rotation, as clearly shown in FIGURE 2. The opposite end of clamp arm 94 is engaged and biased upwardly by a spring 100, which extends therefrom upwardly to a clip 102, suitably engaged under the head of the nearest screw 68. The spring 100, it will be understood, constantly urges the associated end of clamp arm 94 upwardly, whereby the clamp 98 is urged downwardly, and normally maintained in firm contact with the underlying dial cap.

' In alignment with the slot 92 but offset with respect to the horizontal bore 70 is a vertical bore 106, which extends downwardly from the top of the housing 64 to a-substantial depth. Fitted in the bore 106 is a piston 108, the upper surface 110 of which underlies the clamp arm 94 at a point well spaced from its pivot pin 96. An extension 112 from the piston 108 extends along one side of, the clamp arm 94, in guiding relation therewith. A transverse horizontal passage 114 extends from immediately below the horizontal bore 70 to the bottom of the vertical bore 106, and the adapter 74 is drilled as at 116 to provide communication between the interior of the adapter and the horizontal passage 114, and so with the bottom of the piston 108. The latter is chamfered at its bottom, or otherwise formed or disposed, to permit fluid pressure contact therewith effective to elevate the piston.

' As a further novel and important feature of the invention, a small diameter tube 118 extends from the interior of adapter 74 across the outside of the housing 64, terminating in a nozzle 120 directed slightly downwardly against the underlying dial cap, and generally in the direction of cylinder rotation. As shown in FIGURE 2, the nozzle 120 is disposed adjacent the periphery of the dial cap, and accordingly near the encircling needles 44 of the machine.

The pneumatic system, by which pressure air is supplied to pressure conduit 72 at predetermined portions of the knitting machine cycle, is illustrated in FIGURE 22. As there shown, a pressure air line 130 leads to an air valve 132 suitably mounted on the machine. The valve outlet discharges into a small reservoir 134, which in turn communicates with a pressure line such as flexible hose 136 connected to the pressure conduit 72 of the yarn handling mechanism 62. An actuating link 138 is'pivotally mounted at 140, and disposed adjacent and in alignment with the valve stem 142 of the valve 132. The outer end of link 138 is connected by rod 144 to a bell crank 146, pivoted at 148 and maintained by the action of spring 150 in contact with a ring cam 152 mounted on the main drum of the machine. A second valve operating link 154 may be pivotally mounted alongside link 138 to facilitate manual operation of the valve 132. An exemplary ring cam 152, comprising suitably positioned cutaway sections 156, is illustrated in FIG- URE 23.

Beyond the yarn handling mechanism 62, and angularly spaced therefrom in the direction of cylinder rotation by approximately 45, a novel yarn shear is mounted peripherally on the dial cap. To mount the shear in suitable relationship to the needles, the dial plate 162, comprising part of the dial cap 46, is cut away as at 164. A hollow pivot block 166 is mounted in the cutaway portion of the dial plate, by means of the flange 168 which extends therefrom and is secured to the dial cap as by screws 170. Outwardly of the flange 168 is provided a fixed shear blade 172, the shear blade adjoining very closely the periphery of the dial plate. A movable shear blade 174 is pivotally mounted on the pivot block 166, by means of a pivot screw 176 (see FIGURE 15), into which the bolt 178 is threaded. A spring 180 extends between the head of bolt 178 and the opposite interior surface of pivot block 166, and serves to maintain the shear blade 174 in firm pressure contact with the pivot block. The leading end 182 and the trailing end 184 of the movable shear blade 174 are exteriorly rounded as shown, for a purpose hereinafter apparent.

The movable shear blade 174 is engaged by a rod 186 to one arm of a lever 188, which is pivotally supported near its center by the bracket 190. The opposite end of lever 188 is engaged by rod 192 to the operating lever 194 of the machine, which in turn engages and is actuated by the thrust rod 196 (see FIGURE 1). A cap 198 extends from a recess 200 in an underlying portion of the machine frame, and is urged outwardly by spring 202, whereby the cap normally maintains the operating lever in the position illustrated, in firm contact with the thrust rod 196, and the shear in closed position. The thrust rod, it will be understood, is elevated at predetermined intervals by suitable cams on the main drum of the machine, whereby the operating lever 194 is tilted, and the lever 188 correspondingly tilted to open the shear. Exemplary drum cams suitable for such thrust rod actuation are illustrated in FIGURES 24 and 25. For reasons presently apparent, it is desirable that the closing stroke of the shear be gradual rather than sudden, and take place over a brief interval of time corresponding to the passage of several needles of the machine past a fixed point. The drum earn 210 illustrated in FIGURE 24, for example, is provided with a sloping trailing surface 212, which permits the associated thrust rod 196' to ride downwardly from the high surface 214 to the drum surface 216 at a controlled rate. In FIGURE 25, the drum cam 220 comprises the high surface 222, from which the associated thrust rod may descend in stepwise fashion first to the step surface 224 and then to the drum surface 216. As will be understood, stepwise descent of the thrust rod similarly effects shear closing at a controlled rate.

Function and operation of the invention will now be described. Referring initially to FIGURE 1, it may be assumed that the machine is operating in normal roundand-round knitting, as would be the case in knitting a stocking welt. The yarn finger 36" is illustrated in active position, feeding yarn 42 directly into the needles 44 for knitting. The yarn finger 36, in common with the other yarn fingers, is up in inactive position, and the inactive yarn 40 extends therefrom under guide tongue 60 and yarn clamp 98, into the open bottom end of branch passage 84 of the yarn handling mechanism 62, and into the exhaust conduit 80 thereof.

The thrust rod 196 and operating lever 194 are in the position illustrated in FIGURE 1, whereby the shear 160 is in normally closed position. Referring to FIGURE 22, while straight knitting of the yarn 42 proceeds,

the bell crank 146 rides a high portion of the ring cam 152, thereby disposing the actuating link 138 in the position illustrated, out of contact with the stem 142 of valve 132, whereby the valve is in normally closed position. This represents the relationship of the parts while straight knitting proceeds.

When the machine comes to a yarn change, the yarn finger 36 is dropped to active position, by a jog of the main drum, and the hitherto inactive yarn 40 passes between the needles 44 and is taken thereby. Substantially simultaneously, the bell crank 146 (FIGURE 22) is permitted to drop into a low section 156 of the ring cam 152. The spring rotates the bell crank the permitted distance, and through rod 144 rotates the actuating link 138 into contact with stem 142 of valve 132., and displaces the valve stem inwardly to open the air valve. High pressure air immediately flows into reservoir E34 and through flexible hose 136 into the pressure conduit 72 of the yarn handling mechanism 62. The high pressure air fiow enters the horizontal bore 74) of the housing 64 through jet 76, and then passes through the exhaust conduit 80. As will be understood, the high velocity flow through the central section of the horizonal bore 70 effects an aspirating action, creating a suction in the branch passage 84 and causing air flow into the open bottom end thereof.

The free end of the hitherto inactive yarn 4b is engaged by this air flow into the branch passage 84, and by the high velocity flow into the exhaust conduit 89', and thereby drawn taut against the restraining influence of guide tongue 69, yarn finger 36, guide plate 34 and the conventional yarn tensioning and feeding elements of the machine.

Simultaneously, the high pressure air in pressure conduit 72 and adapter 74 passes through drill 116 and transverse passage 114 of the housing 64, and forces the piston 103 upwardly. The piston overcomes the counterbalancing force of spring 180, and elevates the engaged end of the clamp arm 94, and the yarn clamp 98. The clamp arm 94 and the slot 92 are designed, desirably, to limit upward movement of the yarn clamp 98 by engagement of the clamp arm 94, near its engagement to the spring Hill, against the bottom of slot 2, whereby the clamp arm effectively retains the piston in its bore 1%. Access of pressure air to the yarn handling mechanism, then, elfects release of clamp pressure on the inactive yarn, but the inactive yarn is simultaneously engaged and tensioned by the air movement described above. At the same time, also, pressure air passes from the adapter 74 through the tube 118 and its nozzle 129, for a purpose presently apparent.

The same jog of the main drum which drops the yarn finger 35' to active position and opens the air valve 132 may be utilized to open the shear rsa For this purpose, a cam 210' as illustrated in FIGURE 24 or a cam 22E as illustrated in FIGURE 25 may ride under and elevate the thrust rod 1%, to rotate the operating lever 194 in clockwise direction as viewed, moving cap 1% into recess and compressing the spring 2&2. This movement of the operating lever the depresses the engaged rod 193., and rotates the lever 18% to elevate the rod 186 and lift the movable shear blade 174 to open position, illustrated in FIGURE 11 and in dotted lines in FIGURE 10.

FIGURE 16 illustrates the relationship of the mechanism immediately after the finger 36 has dropped to active position. Finger 36" remains in active position, feeding yarn 42 into the needles, and the hitherto inactive yarn 4%} has just been engaged by the needles for knitting. The needle 44' is the first needle to take the yarn 4t and accordingly will be the first needle to knit this yarn. The yarn clamp Q3 is as previously stated in elevated position, and the free end of yarn 40 extends into the exhaust conduit 86 of the yarn handling mechanism, under the control and tensioning effect of air movement.

Momentarily after the yarn 45}: is dropped into the needles, the previously active yarn 42 is withdrawn therefrom, by elevation of its yarn finger 36". Normally, the previously active yarn is withdrawn 1 0 or 15 needles after the hitherto inactive yarn is inserted, providing a yarn lap of about /2 inch. FIGURE 17 illustrates the relationship of the various elements very shortly after the finger 36" has been elevated. 44- represents the last needle to take the yarn 42 for knitting. As illustrated in FIGURE 17, the newly withdrawn yarn 42 extends from the needle 44" to the yarn finger 36". The first needle 44' to take and knit the yarn 40 has advanced in clockwise direction to the position illustrated, the needle having withdrawn this yarn from under the guide tongue 60. The needle 44' has advanced more closelyto the yarn handling mechanism, and the suction eifect of the latter functions to take up the slack in the free end of yarn 4t), and maintain proper tension thereon.

it will be noted that while the newly inserted yarn 4%} is withdrawn by the needles at this stage from under the guide tongue 60, there is no necessity to pull the yarn out against clamp pressure, the pneumatic clamp 98 having been automatically elevated. The newly inserted yarn, accordingly, is not tightened up by clamp pressure, and heavy places or pulled ends in the fabric are effectively avoided. While the clamp pressure is relieved before the newly inserted yarn is pulled out from under the guide tongue, remaining inactive yarns are effectively held and tensioned by suction etfect,whereby they are prevented from being pulled out with the newly inserted yarn. As will be recognized, this too constitutes an outstanding improvement in operation.

The next sequential step in the operation is illustrated in FIGURE 18, wherein the first needle 44' to knit the yarn as has reached a position opposite the yarn handling mechanism. Further slack in the free yarn end has been 'aken up in the branch passage 84 and the exhaust conduit so of the yarn handling mechanism, while effective tension is maintained on this yarn. Meanwhile, yarn 42 has been carried by the last needle 44" to knit this yarn partly around the dial cap, and the yarn end extending from needle 44" to the finger 36 has been drawn under the guide tongue 69.

FIGURE 19 illustrates the relationship of the elements when the first needle 44 to take the yarn 46 has advanced to a position corresponding to or radially aligned with a point well into the V formed by the blades of the now open shear. As the needle 44' advances from the position of FlGURE 18 to that of FIGURE 19, the free end of yarn 4%} must be extended with respect to the branch pas sage 34 of the yarn handling mechanism, and is permitted to pull out under suitable restraining tension, by the nature of the engagement thereof. At this point also, the yarn bight extending from needle 44 to the branch passage 84 isengaged by the air blast issuing from the nozzle of tube 118. This air blast sweeps across the peripheral portion of the dial cap in the vicinity of the shear, and in the direction of needle rotation, and is effective to be'ly out the yarn end so that it extends substantially radially inwardly from the needle 44'. That is, the blast effect of the nozzle 126 is balanced by the restraining suction efliect of the yarn handling mechanism on the engaged yarn end, with the net result that the yarn assumes the relative position illustrated in FIGURE 19.

It will be understood that if the yarn extendsin a straight line from branch passage 84 to the needle 44', it will be disposed across the shear blades at an acute angle. Under these circumstances, even though the shear blades are disposed closely adjacent the needles, on severing the yarn a cut end is left which is considerably greater in length than the radial distance from the shear to the needles, due to the inclination of the yarn. The efiect of the air blast on maining on the fabric is of absolute minimum length.

The withdrawn yarn 42, at the sequential point illusthe yarn, then, is to positlon it for cutting in such manner that the cut end re trated in FIGURE 19, has passed well under the guide tongue 60 (the yarn clamp 98 being still elevated), and has been carried under the undersurface 86 of the yarn handling mechanism, and into contact with the guide post 88. The upward fluid flow into branch passage 84 has engaged the yarn extending thereunder, drawing a loop of the yarn up into the branch passage and exerting tension effect thereon. Beyond the branch passage 84, the yarn end extending to the needle 44 has encountered the blast of nozzle 120, and is bellied out in the manner of the yarn 40.

Since the needles 44 and 44" may be /2 inch or more apart, the difiiculty of shearing both yarns 40 and 42 at the same moment of time will be apparent. The size of the shear blades having a practical limit, the yarn 42 may not be positioned for shearing when the yarn 44 reaches the last possible position for shearing. For this reason, means are provided to close the shear gradually. Referring to FIGURES 1 and 24, the shear is open as the thrust rod 196 rides the high surface 214 of the drum cam 210. At the sequential point illustrated in FIGURE 19, a jog of the main drum rotates cam 210 to permit" the thrust rod 196 to ride down the sloping trailing surface 212 of the cam. This results in a relatively gradual closing of the shear, under the impetus of spring 202, whereby the movable blade 174 pivots over an appreciable period of time corresponding to the passage of several needles. The shear closing is timed to initiate shearing at the point illustrated in FIGURE 19, whereby the free end of newly inserted yarn 40 is sheared off at this point, leaving a cut end on the fabric of inch or less in length. The severed yarn end is exhausted through the exhaust conduit 80, and may be caught in a screen receptacle 230 (FIGURE 22) or the like. Gradual closing of the shear may be attained also by means of the stepped cam 220 illustrated in FIG- URE 25. As will be understood, movement of the main drum permits the thrust rod 196 to ride down first to the step surface 224, and momentarily later to the drum surface 216.

Momentarily later, the withdrawn yarn 40 is carried by the needle 44" to the position illustrated in FIGURE 20, at which time it is well in between the shear blades and is severed. The action of the air blast from nozzle 120, together with the suction engagement and tensioning of the yarn by the branch passage 34, position the yarn in the manner already described, whereby the cut end remaining on the fabric is of minimum length. The relatively slow action of the shear insures that the withdrawn yarn is well between the blades thereof when sevcred. In this manner, both yarns are cut by a single shear stroke, although at slightly different times and at slightly spaced points along the shear blades. It is noteworthy that the outwardly rounded leading and trailing ends 182 and 184 of the movable shear blade 174 permit the shear to be mounted very closely to the needles, further minimizing the length of the cut ends remaining on the fabric.

' When the withdrawn yarn 42 is severed, the end thereof extending from its finger 36" is sucked up through the branch passage 84 and into the exhaust conduit 80, where it remains suitably tensionedand engaged by air movement. This marks the completion of the yarn change, and as illustrated in FIGURE 21, the yarn 40 is feeding into the needles for knitting, and the now inactive yarn 42 is engaged by the yarn handling mecha nism, together with other inactive yarns, in readiness for reinsertion. Thus, at the completion of the yarn change, the end of the withdrawn yarn assumes the position formerly held by the newly inserted yarn, prior to the yarn change. As will be evident, the operation of the device is not limited to two yarns, but three or four or more yarns maybe handledwith equal facility.

The same jog of the main drum which etfects closing of the shear may be utilized to cause the bell crank 146 (FIGURE 22) to ride up out of the engaged cutaway section 156 and onto the high surface of the ring cam 152. The bell crank 146 is by this movement pivoted to the position illustrated in FIGURE 22, against the action of spring 150, displacing the rod 144 and actuating link 138 and permitting the valve stem 142 of valve 132 to move outwardly, whereby the valve is closed. The reservoir 134, however, is effective to maintain pressure air flow for a brief interval of time after closing of the valve 132, adequate to remove the severed end of yarn 40 and to engage the free end of the withdrawn yarn 42 in the yarn handling mechanism.

The air pressure in the adapter 74 and jet 76 drops gradually, permitting the spring to overbalance the elevating pressure effect on piston 108, and to close the clamp Q8. As the suction engagement of the inactive yarns becomes less effective, then, the yarn clamp comes into operation and mechanically engages and holds the inactive yarns. The combined mechanical and suction engagement of the yarns is particularly effective, in that all yarns are engaged at all times, either by mechanical clamping or by air movement. That is, the clamp positively grips the inactive yarns at all times except when the air is on, and air movement positively engages and controls the yarns when the clamp is elevated. The clamp is effective, it will be understood, to keep the inactive yarns in place when the machine head is lifted, when a bobbin is changed, when the machine is racked with the head up, and at other times. Another advantage in herent in operation of the yarn handling mechanism is that all yarns are automatically tightened at every yarn lap. In conventional machines, if a yarn becomes slack between its yarn finger and the yarn clamp, it stays slack until inserted, and on attempted insertion may miss the needles and miss the lap, resulting in a ruined stocking. Also, the yarn handling mechanism by reason of the previously described air movement is self-cleaning. The clamp 98, it has been found, may operate for extended periods of time without attention, whereas yarn clamps 3n conventional machines must be cleaned several times aily.

It will thus be seen that there has been provided by this invention apparatus and methods in which the various objects hereinbefore set forth, together with many practical advantages, are successfully achieved. As various possible embodiments may be made of the several features of the above invention, all without departing from the scope thereof, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative, and not in a limitmg sense.

I claim:

1. In a circular knitting machine having a rotary cylinder with independent needles, a dial cap mounted adjacent the top of said cylinder, a group of individually retractable interchangeable yarn feeds, and yarn severing means disposed peripherally of said dial cap at a point angularly spaced from said yarn feed group in the direction of cylinder rotation, a nozzle disposed above said dial cap at a point leading said yarn severing means and being directed in the direction of cylinder rotation, and means for causing fluid to discharge through said nozzle and across the dial cap during operation of said yarn severing means, whereby yarns extending from said needles adjacent said severing means will be bellied out to extend substantially radially inwardly therefrom.

2. In a circular knitting machine having a rotary cylinder with independent needles, a dial cap mounted adjacent the top of said cylinder, a group of individually retractable interchangeable yarn feeds, and yarn severing means disposed peripherally of said dial cap at a point angularly spaced from said yarn feed group in the direction of cylinder rotation, a conduit having an open end disposed above said dial cap at a point trailing said yarn feed group and leading said yarn severing means in the direction of cylinder rotation, means for inducing air flow into said open end, a nozzle disposed above said dial cap at a point trailing said open end and leading said yarn severing means and being directed in the direction of cylinder rotation, and means for causing air flow through said nozzle.

3. In a circular knitting machine having a rotary cylinder with independent needles, a dial cap mounted adjacent the top of said cylinder, a group of individually retractable interchangeable yarn feeds, and yarn severing means disposed peripherally of said dial cap at a point angularly spaced from said yarn feed group in the direction of cylinder rotation, yarn handling means comprising a conduit having a branch opening above said dial cap at a point trailing said yarn feed group and leading said yarn severing means in the direction of cylinder rotation, a jet in said conduit terminating adjacent the juncture of said branch, means for causing pressure air flow through said conduit and jet to induce air flow into the open end of said branch, and a nozzle disposed above said dial cap at a point trailing said branch opening and leading said yarn severing means and being directed in the direction of cylinder rotation, said nozzle communicating with said conduit.

4. In a circular knitting machine having a rotary cylinder with independent needles, a dial cap mounted adjacent the top of said cylinder, a group or individually retractable interchangeable yarn feeds, and yarn severing means disposed peripherally of said dial cap at a point angularly spaced from said yarn feed group in the direction of cylinder rotation, a conduit having an open end disposed above said dial cap at a point trailing said yarn feed group and leading said yarn severing means in the direction of cylinder rotation, means for inducing air flow into said open end, a yarn clamp mounted above said dial cap between said yarn feed group and said open end, means resiliently urging said clamp into contact with said dial cap, pneumatic means for lifting said clamp away from said dial cap, a nozzle disposed above said dial cap at a point trailing said open end and leading said yarn severing means and being directed in the direction of cylinder rotation, and means for causing air fiow through said nozzle.

5. In a circular knitting machine having a rotary cylinder with independent needles, a dial cap mounted adjacent the top of said cylinder, a group of individually retractable interchangeable yarn feeds, and yarn severing means disposed peripherally of said dial cap at a point angularly spaced from said yarn feed group in the direction of cylinder rotation, yarn handling means comprising a conduit having a branch opening above said dial cap at a point trailing said yarn feed group and leading said yarn severing means in the direction of cylinder rotation, a jet in said conduit terminating adjacent the juncture of said branch, means for causing pressure air flow through said conduit and jet to induce air flow into the open end of said branch, a yarn clamp mounted above said dial cap between said yarn feed group and said open end, means resiliently urging said clamp into contact with said dial cap, pneumatic means communicating with said conduit for liftin said clamp away from said dial cap, and a nozzle disposed above said dial cap at a point trailing said branch opening and leading said yarn severing means and being directed in the direction of cylinder rotation, said nozzle communicating with said conduit.

6. In a circular knitting machine, a dial cap and a yarn handling device mounted above said dial cap, said yarn handling device including a housing, a horizontal bore extending through said housing, a pressure conduit communicating with one end of said bore, an exhaust conduit communicating with the other end of said bore, a branch passage extending downwardly from an intermediate section of said bore and opening above said dial cap, a yarn clamp pivotally mounted on said housing for vertical movement, resilient means urging said clamp 1d downwardly into contact with said dial cap, a vertical bore in said housing, a piston in said vertical bore, said piston engaging said clamp whereby upward movement of said piston will elevate said clamp, and a passage in said housing providing communication between said pressure conduit and the bottom of said vertical bore.

7. In a circular knitting machine, a dial cap and a yarn handling device mounted above said dial cap, said yarn handling device including a housing, a horizontal bore extending through said housing, a pressure conduit communicating with one end of said bore, an exhaust conduit communicating with the other end of said bore, said pressure conduit terminating in a jet directed toward said exhaust conduit, a branch passage extending downwardly from an intermediate section of said bore and opening above said dial cap, a yarn guide post extending downwardly from said housing to said dial cap adjacent said branch passage opening, a yarn clamp pivotally mounted on said housing for vertical movement, resilient means urging said clamp downwardly into contact with said dial cap, a vertical bore in said housing, a piston in said vertical bore, said piston engaging said clamp whereby upward movement of said piston will elevate said clamp, and a passage in said housing providing communication between said pressure conduit and the bottom of said vertical bore.

8. In a circular knitting machine having a rotary cylinder with independent needles, a dial cap mounted adjacent the top of said cylinder, a group of individually retractable interchangeable yarn feeds, and a timing drum controlling the movement of said yarn feeds, a shear disposed peripherally of said dial cap at a point angularly spaced from said yarn feed group in the direction of cylinder rotation, eans actuated by said drum for operating said shear, a nozzle disposed above said dial cap at a point leading said shear and being directed in the direction of cylinder rotation, and means for causing fluid to discharge through said nozzle and across the dial cap during operation of said shear, whereby yarns extending from said needles adjacent the shear will be bellied out to extend substantially radially inwardly therefrom.

9. A circular knitting machine as defined in claim 8, wherein said shear includes a fixed blade set low in said dial cap adjacent the periphery thereof, and a movable blade pivotal on a horizontal axis positioned outwardly of said fixed blade, the leading and trailing ends of said movable blade being outwardly rounded to clear said needles.

10. A circular knitting machine as defined in claim 8, wherein said means for operating said shear includes a drum cam shaped to close said shear over a discrete period of time corresponding to the passage of several needles to thereby sever a plurality of yarns in a single stroke.

11. In the operation of a circular knitting machine having a rotary cylinder with independent needles, a dial cap mounted adjacent the top of said cylinder, 21 group of individually retractable interchangeable yarn feeds, and yarn severing means disposed peripherally of said dial cap at a point angularly spaced from said yarn feed group in the direction of cylinder rotation, the method compris ing the steps of applying tension to a yarn end being carried by said needles over said dial cap, directing an air blast at said yarn end between the point of tension ap plication and said yarn severing means as said yarn end moves into proximity to said yarn severing means, said air blast being directed across the d al cap in the direction of cylinder rotation whereby said yarn end is bellied out to exte d substantially radially inwardly from said needles, and severing said yarn end while so positioned by said air blast.

12. In the operation of a circular knitting machine having a rotary cylinder with independent needles, a dial cap mounted adjacent the top of said cylinder, a group spams"? of individually retractable interchangeable yarn feeds, and yarn severing means disposed peripherally of said dial cap at a point angularly spaced from said yarn teed group in the direction of cylinder rotation, the method comprising the steps of applying suction to a yarn end being carried by said needles over said dial cap, directing an air stream at said yarn end between the point of suction application and said yarn severing means as said yarn end moves into proximity to said yarn severing means, said air stream being directed in the direction of cylinder rotation whereby said yarn end is bellied out to extend substantially radially inwardly from said needles, and severing said yarn end while so positioned by said air stream.

13. In the operation of a circular knitting machine having a rotary cylinder with independent needles, a dial cap mounted adjacent the top of said cylinder, a group of individually retractable interchangeable yarn feeds, and a shear disposed peripherally of said dial cap at a point angularly spaced from said yarn feed group in the direction of cylinder rotation, the method comprising the steps of applying tension to an inactive yarn end extending over said dial cap at a point trailing said yarn feed group and leading said shear in the direction of cylinder rotation, inserting said inactive yarn while so tensioned into the needles for knitting, directing an air stream at said yarn end between the point of tension application and said shear as said yarn end is carried by said needles into proximity to said shear, said air stream being directed in the direction of cylinder rotation whereby said yarn end is bellied out to extend substantially radially inwardly from said needles, and shearing said yarn end while so positioned by said air stream.

14. In the operation of a circular knitting machine having a rotary cylinder with independent needles, a dial cap mounted adjacent the top of said cylinder, a group of individually retractable interchangeable yarn feeds, and a shear disposed peripherally of said dial cap at a point angularly spaced from said yarn feed group in the direction of cylinder rotation, the method comprising the steps of applying tension to an inactive yarn end extending over said dial cap by suction applied at a point trailing said yarn feed group and leading said shear in the direction of cylinder rotation, inserting said inactive yarn While so tensioned into the needles for knitting, directing an air stream at said yarn end between the point of suction application and said shear as said yarn end is carried by said needles into proximity to said shear, said air stream being directed in the direction of cylinder rotation whereby said yarn end is bellied out to extend substantially radially inwardly from said needles, shearing said yarn end while so positioned by said air stream, and then removing the several yarn end by means of said suction.

15. In the operation of a'circular knitting machine having a rotary cylinder with independent needles, a dial cap mounted adjacent the top of said cylinder, a group of individually retractable interchangeable yarn feeds, and a shear disposed peripherally of said dial cap at a point angularly spaced from said yarn feed group in the direction of cylinder rotation, the method comprising the steps of withdrawing a yarn from active knitting by retraction of one of said yarn feeds, whereby said yarn is carried by the last needle to knit around said cylinder and over said dial cap, applying tension to the withdrawn yarn end at a point trailing said yarn feed group and leading said shear in the direction of cylinder rotation, directing an air stream at said yarn end between the point of tension application and said shear as said yarn end is carried by the last needle to knit into proximity to said shear, said air stream being directed in the direction of cylinder rotation whereby said yarn end is bellied out to extend substantially radially inwardly from said needles, shearing said yarn end while so positioned by 12 said air stream, and retaining the several yarn end at the point of tension application.

16. In the operation of a circular knitting machine having a rotary cylinder with independent needles, a dial cap mounted adjacent the top of said cylinder, a group of individually retractable interchangeable yarn feeds, and a shear disposed peripherally of said dial cap at a point angularly spaced from said yarn feed group in the direction of cylinder rotation, the method comprising the steps of withdrawing a yarn from active knitting by retraction of one of said yarn feeds, whereby said yarn is carried by the last needle to knit around said cylinder and over said dial cap, applying tension to the withdrawn yarn end by suction applied at a point trailing said yarn feed group and leading said shear in the direction of cylinder rotation, directing an air stream at said yarn end between the point of suction application and said shear as said yarn end is carried by the last needle to knit into proximity to said shear, said air stream being directed in the direction of cylinder rotation whereby said yarn end is bellied out to extend substantially radially inwardly from said needles, shearing said yarn end while so positioned by said air stream, and engaging the sev yarn end by means of said suction.

In the operation of a circular knitting machinehaving a rotary cylinder with independent needles, a dial cap mounted adjacent the top of said cylinder, a group of individually retractable interchangeable yarn feeds, and a shear disposed peripherally of said dial cap at a point angularly spaced from said yarn feed group in the direction of cylinder rotation, the method comprising the steps of applying tension to an inactive yarn end extending over said dial cap at a point trailing said yarn feed group and leading said shear in the direction of cylinder rotation, inserting said inactive yarn while so tensioned into the needles for knitting, then withdrawing a yarn from active knitting by retraction of one of said yarn feeds, whereby said yarn is carried by the last needle to knit around said cylinder and over said dial cap, applying tension to said withdrawn yarn, and shearing said yarn ends sequentially by a single stroke of said shear.

18. In the operation of a circular knitting machine having a rotary cylinder with independent needles, a dial cap mounted adjacent the top of said cylinder, a group of individually retractable interchangeable yarn feeds, and a shear disposed peripherally of said dial cap at a point angularly spaced from said yarn feed group in the direction of cylinder rotation, the method comprising the steps of applying tension to an inactive yarn end extendng over said dial cap by suction applied at a point trailmg said yarn feed group and leading said shear in the direction of cylinder rotation, inserting said inactive yarn while so tensioned into the needles for knitting, then Withdrawing a yarn from active knitting by retraction of one of said yarn feeds, whereby said yarn is carried by the last needle to knit around said cylinder and over said dial cap, applying tension to said withdrawn yarn by means of said suction, directing an air stream at said yarn ends between the point of suction application and said shear as said yarn ends are carried by said needles into proximity to said shear, said air stream being directed in the direction of cylinder rotation whereby said yarn ends are bellied out to extend substantially radially inwardly from said needles, shearing said yarn ends while so positioned by said air stream sequentially by a single stroke of said shear, removing the severed newly inserted yarn end by means of said suction, and engaging the severed withdrawn yarn end by means of said suction.

19. In a circular knitting machine having a circle of cylinder needles, a dial positioned inside of said circle of needles, and a plurality of movable yarn feeding fingers to feed and withdraw yarns relative to said needles; the combination therewith of yarn cutting means to si-' multaneously sever the leading end of a yarn fed to the needles and the trailing end of a yarn withdrawn from needles comprising a fixed cutting blade carried by said dial and a movable cutting blade cooperating with said fixed cutting blade, pattern controlled means for moving said movable blade and suction means for creating suction currents to attract the yarn ends severed by said yarn cutting means, said suction means comprising a suction nozzle disposed in the path of yarns extending from said yarn cutting means to said yarn feeding fingers.

20. In a circular knitting machine having a rotary cylinder with independent needles, a dial cap mounted adjacent the top of said cylinder and a plurality of individually retractable yarn feeding fingers, yarn severing means disposed peripherally of said dial cap at a point angularly spaced from said yarn feeding fingers in the direction of cylinder rotation, said severing means comprising a fixed cutting blade carried by said dial cap and a movabut cutting blade cooperating with said fixed cutting blade, and pattern controlled means for moving said 14 movable blade to sever in a single stroke yarns from a plurality of the yarn feeding fingers.

21. A circular knitting machine as defined in claim 20 wherein said pattern controlled means includes a cam shaped to close said movable blade over a discrete period of time corresponding to the passage or" several needles.

References (Jited in the file of this patent UNITED STATES PATENTS 1,237,256 Scott Aug. 14, 1917 1,836,720 Lawson et al. June 21, 1932 2,269,757 Davis Jan. 13, 1942 2,424,033 Hilker et a1 July 15, 1947 2,560,484 Schoenster et a1. July 10, 1951 2,580,513 Brown lan. 1, 1952 2,712,805 Peterson et a1 July 12, 1955 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION February 12 1963 Patent Non 3 OTZ O97 Vaughn H Butler It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

column ll Column 2 line 65' for "at" read as and column 12 line l for "severaP each occurrence line l before "needles" insert line 53 read M severed column 13,,

ober 1963o Signed and sealed this 8th day of Oct (SEAL) EDWIN Ln REYNOLDS Attest:

AC 13 1 ng Commissioner of Patents ERNEST W. SWIDER Attesting Officer 

1. IN A CIRCULAR KNITTING MACHINE HAVING A ROTARY CYLINDER WITH INDEPENDENT NEEDLES, A DIAL CAP MOUNTED ADJACENT THE TOP OF SAID CYLINDER, A GROUP OF INDIVIDUALLY RETRACTABLE INTERCHANGEABLE YARN FEEDS, AND YARN SEVERING MEANS DISPOSED PERIPHERALLY OF SAID DIAL CAP AT A POINT ANGULARLY SPACED FROM SAID YARN FEED GROUP IN THE DIRECTION OF CYLINDER ROTATION, A NOZZLE DISPOSED ABOVE SAID DIAL CAP AT A POINT LEADING SAID YARN SEVERING MEANS AND BEING DIRECTED IN THE DIRECTION OF CYLINDER ROTATION, AND MEANS FOR CAUSING FLUID TO DISCHARGE THROUGH SAID NOZZLE AND ACROSS THE DIAL CAP DURING OPERATION OF SAID YARN SEVERING MEANS, WHEREBY YARNS EXTENDING FROM SAID NEEDLES ADJACENT SAID SEVERING MEANS WILL BE BELLIED OUT TO EXTEND SUBSTANTIALLY RADIALLY INWARDLY THEREFROM. 